KR20070042198A - Heat resistant adhesive film and electromagnetic steel sheet with said heat resistant adhesive film, iron core using said electromagnetic steel sheet, and process for manufacturing the same - Google Patents

Abstract

The present invention provides an electronic steel sheet surface-coated with a heat-resistant adhesive insulating film which can be bonded by pressure and heating after lamination, and can be subjected to strain removal annealing, an iron core using the same, and a method of manufacturing the same. An electrical steel sheet coated with a heat-resistant adhesive insulating film containing a resin softened at or below C and a low melting inorganic component having a softening point temperature of 1000 ° C. or less measured by a differential thermal analysis method is obtained. By laminating | stacking and pressure-fixing this electronic steel plate, the adhesive fixation core which can perform deformation | transformation removal annealing can be obtained.

Heat-resistant adhesive insulation film, electronic steel sheet, strain removal annealing

Description

Heat-resistant adhesive film, an electronic steel plate with a heat-resistant adhesive film coated thereon, an iron core using the electronic steel plate, and a method for producing the same AND PROCESS FOR MANUFACTURING THE SAME}

After lamination | stacking, this invention can adhere | attach by pressurization and heating (The heat treatment of room temperature or more and 300 degrees C or less unless otherwise indicated in this invention), and after that, annealing treatments, such as strain removal annealing (this invention) Refers to a heat-resistant adhesive film composition and a surface-coated electrical steel sheet capable of maintaining adhesive performance even if the heat treatment is higher than 300 ° C unless otherwise specified.

An electrical steel sheet is mainly used as iron cores, such as a motor and a transformer. Usually, an insulating film is formed on the surface of an electrical steel sheet, and it is common to form an iron core integrally by the method which engages in uneven | corrugated parts, such as welding or caulking, after laminating | stacking continuously in a predetermined shape and engaging.

The integrated iron core is used to be assembled and used as it is to an electric device, and there are ones which are assembled to an electric device after annealing at a temperature of about 700 to 800 ° C. The latter annealing is called strain elimination annealing, and it removes or reduces shear deformation introduced into steel sheet during punching / shearing, thermal deformation caused by welding of cross section or plastic deformation of caulking part, etc. For the purpose of heightening, it is carried out on iron cores used in electrical appliance applications where high electrical efficiency is required.

In the method of integrating the laminated steel sheet by welding or caulking, there is a problem in that the iron core edge portion is short-circuited and the insulation is deteriorated, and the magnetic properties are deteriorated due to work deformation. As a method of avoiding defects due to welding or caulking, a technique has been proposed in which an insulating film that exhibits adhesiveness by thermal compression is formed on an electronic steel sheet in advance, punched or sheared, and then laminated and thermally compressed.

For example, the manufacturing method of the adhesive surface-coated electrical steel plate characterized by apply | coating the liquid mixture which has the acryl-modified epoxy resin emulsion which mix | blended a latent hardener as a main component, and incompletely heat-cures (Japanese Patent Publication No. 2613725), Electronic steel sheet with insulating coating coated with an adhesive resin containing a blowing agent (JP-A-2002-260910), JP-A-55-9815, and JP-A-2-208034 This has been proposed. These so-called adhesive coating techniques can alleviate problems caused by caulking and welding. However, since the surface of the steel sheet is coated only with organic materials, most of them are decomposed at a temperature of 300 ° C. or higher, and the adhesive force cannot be maintained when the strain removal annealing is performed. Therefore, an electronic steel sheet coated with an adhesive coating can be used for the iron core not subjected to strain removal annealing, but there is a problem that cannot be used for iron cores subjected to deformation removal annealing for reducing iron loss.

On the other hand, after deforming annealing the steel sheet processed into a predetermined shape by punching or the like, a method of fixing with an adhesive can also be considered. However, workability is poor because an adhesive must be applied to every small punched piece.

In addition, Japanese Unexamined Patent Publication No. 42-24519, Japanese Unexamined Patent Application Publication No. 58-128715, and Japanese Unexamined Patent Publication No. 47-47499 disclose a coating containing no resin component, so-called inorganic coating. Japanese Unexamined Patent Publication No. 42-24519 does not have a bonding function between steel sheets, and thus, an integrated iron core cannot be obtained unless a fixing method other than bonding such as caulking or welding is performed. Japanese Patent Application Laid-Open Nos. 58-128715 and 47-47499 have a problem in that the film is hard, has a bad effect on the punching mold, and has a lot of dust because it is an inorganic film composed of only a low melting point glass component.

The present invention provides a heat-resistant adhesive insulating film that maintains the adhesion state and insulation even after deformation removal annealing by improving the heat resistance of the adhesive insulating film of the adhesive steel sheet with an adhesive insulating film, and an electronic steel sheet with a heat-resistant adhesive coating coated thereon, An iron core using the electrical steel sheet and a manufacturing method thereof are provided.

In order to solve the said subject, this invention uses the following means.

(1) A heat-resistant adhesive insulating film comprising a resin having a softening point temperature of not less than room temperature and not more than 300 ° C, and a low melting point inorganic component having a softening point temperature of not higher than 1000 ° C.

(2) The heat-resistant adhesive insulating film according to (1), wherein 250 ° C adhesive strength = 10 kg / cm ² or more and 750 ° C adhesive strength = 1 kg / cm ² or more.

(3) The heat-adhesive resistance according to ( ¹ ), wherein the linear thermal expansion coefficient at 30 ° C to 300 ° C is 10 × 10 ⁻⁷ (° C. ⁻¹ ) or more and 150 × 10 ⁻⁷ (° C. ⁻¹ ) or less. Insulation film.

(4) The heat-resistant adhesive insulating film according to (1), wherein the low-melting-point inorganic component is an additional mixture of low-melting-point glass frit, water glass, or colloidal silica.

(5) The heat-resistant adhesive insulating film according to (4), wherein the average particle diameter of the low melting inorganic component is 20 µm or less.

(6) The heat-resistant adhesive insulating film according to (4), wherein the mixing ratio of the resin to the low melting inorganic component is 20% or more and 500% or less by mass fraction.

(7) The heat-resistant adhesive insulating film according to (4), wherein the low melting inorganic component is a SiO ₂ -B ₂ O ₃ -R ₂ O system low melting point glass (R is an alkali metal).

(8) The heat-resistant adhesive insulating film according to (4), wherein the water glass is soda silicate.

(9) The resin or siloxane polymer according to (1), wherein the resin is an epoxy resin, an acrylic resin, a phenol resin, or a resin or siloxane polymer obtained by heat-curing incompletely a mixed solution containing, as a main component, an acrylic modified epoxy resin emulsion containing a latent curing agent in advance. A heat-resistant adhesive insulating film comprising one kind or two or more kinds thereof.

(10) An electrical steel sheet with a heat-resistant adhesive insulating film having a film as described in (1) on at least one side of the steel sheet.

(11) The electrical steel sheet with a heat-resistant adhesive insulating film according to (10), wherein the film thickness of the heat-resistant adhesive insulating film is 0.5 µm or more and 20 µm or less.

(12) Iron core using the electrical steel plate with a heat-resistant adhesive insulating film of (10).

(13) Preparation of the iron core using the electronic steel plate with a heat-resistant adhesive insulating film obtained by laminating and pressing and fixing the electronic steel sheet of (10) to produce an electronic steel sheet laminate, followed by annealing at 600 to 900 ° C to obtain an integrated iron core. Way.

(14) The method for producing an iron core according to (13), wherein the electronic steel sheet with a heat-resistant adhesive insulating film is formed by heating at least in the step of pressure fixing, adhesive fixing, fixing by caulking or jig, or using them in combination. .

This invention composites the composition of the insulating film of an electrical steel plate, and has two types of adhesiveness, As a specific means, Resin softened at room temperature or more and 300 degrees C or less, and the low softening point temperature measured by the differential thermal analysis method is 1000 degrees C or less. It is a film containing a melting point inorganic component. The resin of the coating is softened at the time of hot pressing to bond and integrate the iron core, and the low-melting-point inorganic component serves to keep the iron core in an integrated state during the deformation removal annealing of the iron core.

In order to remove a deformation | transformation from a steel plate, as an annealing temperature, the temperature of about 700 to 800 degreeC is normally needed. At such annealing temperature, the organic matter is decomposed to maintain the structure, and thus the adhesiveness cannot be maintained. MEANS TO SOLVE THE PROBLEM The present inventors focused on the inorganic compound as the thing which can maintain a structure even at the high temperature of 700 degreeC to 800 degreeC, and can exhibit the adhesiveness between steel sheets, and examined various inorganic compounds repeatedly. As a result, it was found that a group of low-melting-point inorganic components called so-called low-melting glass frits and low-melting-point inorganic components such as water glass and colloidal silica exhibited good adhesion between the steel sheets at annealing temperature conditions of around 750 ° C. However, only such a low-melting-point inorganic component does not exhibit adhesiveness at the stage before completion of annealing, and therefore cannot maintain the iron core integrally. Therefore, it was found that by compounding these resins, an iron core capable of adhesive fixation before strain removal annealing and retaining adhesive fixation performance even after strain removal annealing can be obtained.

Hereinafter, the low melting inorganic component is demonstrated first. The inventors have found that it is the softening point temperature of the low-melting-point inorganic component that determines whether or not the adhesive action is in the strain removal annealing temperature region.

Hereinafter, the experimental content for completing the invention will be described in detail.

In order to confirm the importance of the softening point temperature, the present inventors manufactured a sample under the following conditions and examined the adhesive strength thereof. First, a large number of non-oriented electrical steel sheets having a plate thickness of 0.5 mm and no insulating film formed on the surface were prepared. A low melting point glass frit having an average particle diameter of 5 占 퐉 and various softening point temperatures as a low melting point inorganic component, and an epoxy resin: acrylic resin: phenol resin = 15: 3: 3 (mass%) as a resin and a solid content fraction of 20 mass Both were mixed using% water emulsion and applied with a roll coater. The mixing ratio of the resin to the glass frit was 100% in the solid content ratio, i.e., the same mass. The coating amount was 8 g / m ² per side and dried at a plate temperature of 160 ° C. In this way, the test piece was cut out from the produced sample. Next, 250 degreeC adhesive strength and 750 degreeC adhesive strength were measured.

Here, the softening point temperature is the temperature of the inflection point observed in the measurement curve of the differential thermal analysis method shown in FIG. 1 after the start of measurement, or JIS-R3103-1 "Super softening point test method" (ISO 7884-6: 1987). , ASTM C338) refers to the lower temperature, but if it is difficult to measure by any of the above method may be replaced by another softening point temperature.

In addition, 250 degreeC adhesive strength is 10 cm of rolling direction length, and 2 samples of length of 3 cm orthogonal to a rolling direction WHEREIN: The pressing force 10kg / 3cm <^2> and heating temperature 250 degreeC in the state which overlapped with 1 cm of short sides and an area of 3 cm <^2> . After bonding under conditions of a heating time of 60 seconds, the value obtained by dividing the strength at the time of pulling and peeling in the rolling direction at room temperature by an area of 3 cm ² . Further, in the present invention, the pressing force and the adhesive strength are obtained by dividing the indicated value (kg) of the spring scale by the area, but using kg / cm ² , which corresponds to 9.8 × 10 ⁴ Pa.

In addition, 750 degreeC adhesive strength means that the sample adhere | attached on the said low temperature adhesion conditions was heated under the conditions of the heating temperature of 750 degreeC and the heating time for 2 hours in the state which is not pressurized further, and it peeled by peeling at room temperature in the rolling direction. The intensity of the time divided by the area 3cm ² . The results are shown in Table 1.

In Table 1, when the glass frit whose softening point temperature of condition number 1 to the condition number 8 is 1000 degrees C or less is used, 250 degreeC adhesive strength is 10 kg / cm <^2> or more, and 750 degreeC adhesive strength is 1 kg / cm <^2> , It can be seen that both values are good. On the other hand, when the glass frit having the softening point temperature of condition No. 9 is 1050 ° C, the 250 ° C adhesive strength is good at 10 kg / cm ² , but the 750 ° C adhesive strength is such that the adhesive surface easily peels off after annealing and cannot be measured. Weak. As mentioned above, when the glass frit whose softening point temperature was 1000 degrees C or less was used, it turned out that the characteristic of both is 250 degreeC adhesive strength 10 kg / cm <^2> or more and 750 degreeC adhesive strength 1kg / cm <^2> .

Next, the present inventors consider the following mechanism about the reason that 750 degreeC adhesive strength depends on the softening point temperature of a low melting-point inorganic component. Resin softens and melt | dissolves at the time of pressurization and heating adhesion in the vicinity of 250 degreeC, and in the case of double-side coating, a film interface disappears and adhesion between films is achieved. However, at this stage, the low melting point inorganic component with high temperature stability hardly caused a reaction. Next, at the time of heating at 750 degreeC, the low melting inorganic component softens (melting according to the kind of low melting inorganic component) this time, and the low melting inorganic components which contact are combined. As a result, opposing coatings are integrated to complete adhesion of the steel sheets. Therefore, it is important for the low melting point inorganic component to soften or melt in the heating step near 750 ° C.

As shown in Condition No. 9 in Table 1, in the low melting point inorganic components having a high softening point temperature, even if the low melting point inorganic components are in contact with each other, since softening does not proceed in the temperature range of 750 ° C, sufficient contact area between the low melting point inorganic components is achieved. Can't get it. Therefore, the bond between the low melting inorganic components is not formed sufficiently. As a result, adhesive strength cannot be obtained.

On the other hand, in the low melting point inorganic components having a low softening point temperature as in the condition numbers 1 to 8 of Table 1, the softening proceeds in the temperature range of 750 ° C. when the low melting point inorganic components are in contact with each other. A constant contact area can be obtained. Thus, bonds between low melting inorganic components are formed. As a result, adhesive strength can be obtained.

In addition, even in low melting point inorganic components having a softening point temperature higher than 750 ° C., which is a heating temperature of 880 ° C. or 1000 ° C., the reason why a constant 750 ° C. adhesive strength can be obtained is not fully understood. Even in the low melting point inorganic component, it is assumed that a kind of softening-like reaction occurs in the temperature range of 750 ° C., and the low melting inorganic components are bonded to each other to realize film integration and steel plate adhesion.

The 250 degreeC adhesive strength made 10 kg / cm <^2> or more defines the adhesive strength which can be handled without peeling in the manufacturing process until temporary fixation after temporary fixation by adhesion | attachment at low temperature. In addition, setting 750 degreeC adhesive strength to 1 kg / cm <^2> or more defines the adhesive strength which does not peel after assembling to an electrical apparatus.

As the low-melting-point inorganic component of the present invention, a low-melting-point glass frit, water glass, or a mixture of colloidal silica and the like can be used.

When the low melting inorganic component used is an inorganic powder, the particle size is also important. If the particle diameter is too large, coarse protrusions are formed on the surface of the coating, which prevents contact between the coatings. In order to realize sufficient contact between films or between powders, it is preferable that the average particle diameter of the low melting inorganic component used is 20 micrometers or less. In particular, it is preferable that average particle diameter is 4 micrometers or less, especially 3 micrometers or less.

Next, the present inventors examined the mixing ratio of the low melting inorganic component and the resin.

First, a large number of non-oriented electrical steel sheets having a plate thickness of 0.35 mm and having an insulating film mainly composed of magnesium chromate on the surface were prepared. On the other hand, as a low melting inorganic component, a low melting glass frit having an average particle diameter of 3 µm and a softening point temperature of 550 ° C. (B ₂ O ₃ = 30%, SiO ₂ = 20%, BaO = 30%, Na ₂ O = 10%) , ZnO = 10%), and a water emulsion liquid having a resin composition of epoxy resin: acrylic resin: phenol resin = 20: 5: 3 (mass%) and a solid content fraction of 20 mass% were mixed and applied by a roll coater. At this time, it prepared so that the mixing ratio of resin with respect to glass frit might become various values. The film amount was 5 g / m <^2> per side, and it dried at the plate temperature of 150 degreeC. In this way, the test piece was cut out from the produced sample. Next, 250 degreeC adhesive strength and 750 degreeC adhesive strength were measured. The results are shown in Table 2.

In Table 2, when the condition number 2 to the condition number 6, that is, the resin / glass frit mixing ratio is 20% or more and 500% or less, the 250 ° C. adhesive strength is 10 kg / cm ² or more, and the 750 ° C. adhesive strength is 1 kg / cm. ^{It is 2} and it turns out that both values are favorable. On the other hand, in the condition that the resin / glass frit mixing ratio of condition No. 1 was 10%, both the 250 ° C. adhesive strength was 5 kg / cm ² and the 750 ° C. adhesive strength was 0.5 kg / cm ² . In addition, on the condition that the resin / glass frit mixing ratio of condition No. 7 was 700%, 250 degreeC adhesive strength was favorable as 40 kg / cm <^2> , but 750 degreeC adhesion was low as 0.5 kg / cm <^2> . From the above, when the mixing ratio of the resin / glass frit is 20% or more and 500% or less, it can be seen that both the 250 ° C adhesive strength and the 750 ° C adhesive strength are good.

In addition, the present inventors consider the following mechanism about the reason why adhesive strength depends on the resin ratio with respect to a low melting-point inorganic component. Resin has the adhesive function at the time of 250 degreeC heating, and the low melting-point inorganic component shares the adhesive function at the time of 750 degreeC heating, respectively. Therefore, the resin / low melting point inorganic component ratio dependence mechanism with respect to adhesive strength can be estimated by considering whether both are in the state which can function at each heating temperature. That is, the 250 ° C. adhesive strength takes into account the surface occupied state of the organic resin that bonds when heated at 250 ° C., and the 750 ° C. adhesive strength takes into account the surface occupied state of the low melting inorganic component that performs adhesion upon heating at 750 ° C., respectively. Just do it.

When the ratio of the resin to the low-melting-point inorganic component is small, for example, as in condition No. 1 in Table 2, most of the surface is occupied by the low-melting-point inorganic component and almost no resin can be found on the surface. In such a case, even if the films are overlapped and heated to 250 ° C. in a pressurized state, the resins cannot be sufficiently contacted because the resins cannot have sufficient contact areas. Therefore, the 250 ° C. adhesive strength is a small value (for condition number 1, 250 ° C. adhesive strength = 5 kg / cm ² ). Even if the low melting inorganic component is softened and melted by heating at 750 ° C. in a state where sufficient adhesion is not realized at 250 ° C. heating, if the contact between the films is not sufficiently realized at 250 ° C. heating, the low melting point inorganic components are in contact with each other. Coupling cannot be realized sufficiently. As a result, the 750 ° C. adhesive strength is also a small value (for condition No. 1, 750 ° C. adhesive strength = 0.5 kg / cm ² ). When the ratio of resin to low melting inorganic component is too small by such a mechanism, both 250 degreeC adhesive strength and 750 degreeC adhesive strength show low values.

On the other hand, when the mixing ratio of the resin to the low-melting-point inorganic component is large, the resin is sufficiently present on the surface of the film, and the resin sufficiently adheres when heated to 250 ° C., so that a large adhesive strength can be obtained (in the case of condition 7, 250 ° C. adhesive strength = 40 kg / cm ² ). However, when heating at 750 ° C., there is not enough low-melting point inorganic component on the surface of the coating to exhibit an adhesive function, so the 750 ° C. adhesive strength is small (in case of condition No. 7, 750 ° C. adhesive strength = 0.5 kg). / cm ² ).

In addition, the coefficient of linear thermal expansion of the low-melting-point inorganic components 10 × 10 ^-7 (℃ ^-1) more than ^{150 × 10 -7 (℃ -1)} , the magnetic properties at the time of forming the iron core by less in from 30 ℃ to 300 ℃ The nonuniformity of can also be prevented.

The inventors produced a steel sheet with a film and an iron core made of the steel sheet under the following conditions, and examined their magnetic properties. First, a large number of non-oriented electrical steel sheets having a plate thickness of 0.5 mm and no insulating film on the surface were prepared. On the other hand, as the low melting point inorganic component, a low melting point glass frit having an average particle diameter of 5 µm and various thermal expansion coefficients and an epoxy resin: acrylic resin: phenol resin = 10: 4: 5 (mass%) and a solid content fraction of 20 mass % Water emulsion was mixed and applied with a roll coater. The mixing ratio of the resin to the glass frit was 200% in terms of solid content. The film amount was 10 g / m ² per side and dried at a plate temperature of 150 ° C.

From these samples, an annular sample having an inner diameter of 10.16 cm (4 inches) and an outer diameter of 12.7 cm (5 inches) was prepared, and 20 sheets were laminated and heated for 4 hours at a pressure of 10 kg / cm ² at a temperature of 250 ° C. An iron core was produced. Next, the iron core was annealed at a temperature of 750 ° C. for 2 hours without pressing the iron core. Finally, the iron loss was measured at a frequency of 50 Hz and a magnetic flux density of 1.5 tesla. The results are shown in Table 3.

In Table 3, the linear thermal expansion coefficients of the low-melting-point inorganic component at condition number 2 to condition number 9, that is, at 30 ° C. to 300 ° C. are 10 × 10 ⁻⁷ (° C. ⁻¹ ) or more and 150 × 10 ⁻⁷ ( It can be seen that the iron loss at the time of forming the iron core after annealing is smaller than 3.1 (W / kg) and satisfactory when the temperature is lower than or equal to ^-1 ° C. On the other hand, when the glass frit having the linear thermal expansion coefficient of Condition No. 1 was 160 × 10 ⁻⁷ (° C. ⁻¹ ), the iron loss value was 3.27 (W / kg), and the linear thermal expansion coefficient of Condition No. 10 was 5 ×. Even when a glass frit of 10 ⁻⁷ (° C. ⁻¹ ) was used, the iron loss value was 3.26 (W / kg). When the linear thermal expansion coefficient of the low-melting-point inorganic component at 30 ° C to 300 ° C is 10 × 10 ⁻⁷ (° C ⁻¹ ) or more and 150 × 10 ⁻⁷ (° C ⁻¹ ) or less, at the time of forming the iron core after annealing Good iron loss was found.

The present inventors consider the following mechanism for the reason that the iron loss in the iron core state after annealing depends on the linear thermal expansion coefficient of the low melting inorganic component. Resin in a film softens and melts by pressurization and heat adhesion at 250 degreeC, and in the case of double-sided application, a film interface disappears and adhesion between films is implement | achieved. However, at this stage, the low melting point inorganic component with high temperature stability hardly caused a reaction. Next, at the time of heating at 750 degreeC, the low melting inorganic component will fuse | melt and contact | connect the low melting inorganic components which melt and contact according to the kind of softening and low melting inorganic component at this time. As a result, opposing coatings are integrated to complete adhesion of the steel sheets. Then, the iron loss value is measured after cooling to room temperature. Here, what should be considered is a problem of stress generated in the forming iron core when the surface of the steel sheet is bonded to the entire surface in the high temperature state of 750 ° C. and cooled to room temperature.

In general, the magnetic properties deteriorate when stress acts on the iron core. Here, the relationship between the thermal expansion coefficient of a substance and a stress is demonstrated. In general, when a material having a high coefficient of thermal expansion and a material having a low coefficient of thermal expansion are bonded to a high temperature and cooled to room temperature, a tensile stress is applied to a material having a large coefficient of thermal expansion and a compressive stress is applied to a material having a small coefficient of thermal expansion, respectively. The linear thermal expansion coefficient of an electrical steel sheet is also 100 * ^10-7 (degreeC- ¹ ) of a grain-oriented electrical steel sheet and a non-oriented electrical steel sheet generally. On the other hand, the thermal expansion coefficient of the low melting-point inorganic component used for experiment is 5 * 10 <^-7> (degreeC- ¹ ) to 160 * 10 <^-7> (degreeC- ¹ ). Therefore, when an inorganic powder having a coefficient of thermal expansion smaller than that of the steel sheet is used, a tensile stress acts on the forming iron core when an inorganic powder having a coefficient of thermal expansion larger than the steel sheet is used.

Considering this experiment, in the case of the inorganic powder having the largest linear thermal expansion coefficient under condition number 1, the compressive force with respect to the molded iron core has a large compressive force, and in the case of the inorganic powder having the smallest linear thermal expansion coefficient under condition number 10, the molded iron core It is assumed that a large tensile stress is applied to each. The molded iron cores of condition No. 1 and condition No. 10, which have a difference between the steel sheet and the largest coefficient of linear thermal expansion, and are therefore considered to have the greatest stress, are considered to have a large iron loss value due to this stress application. On the other hand, in the case of condition No. 2 to condition No. 9, the coefficient of thermal expansion of the used inorganic powder is different from the coefficient of thermal expansion of the steel sheet, but since the difference is small, the value is small even if the tensile stress or the compressive stress on the forming iron core is applied. As a result, it is assumed that there was no significant effect on the iron loss value.

The low-melting-point inorganic component of the present invention contributes to the adhesive expression after strain removal annealing, and it is preferable that the softening point is a low melting point glass of 750 ° C. or lower which is a normal strain removal annealing temperature. The low melting glass is softened and melted during strain removal annealing to solidify by cooling, and two plates can be bonded after strain removal annealing. As the composition of the low melting glass, SiO ₂ -B ₂ O ₃ -R ₂ O (R is an alkali metal) type, P ₂ O ₅ -R ₂ O (R is an alkali metal) type, SiO ₂ -PbO-B ₂ O ₃ there may be mentioned _{type, B 2 O 3 -Bi 2 O} 3 based, SiO ₂ -B ₂ O ₃ -ZnO-based, SnO-P ₂ O _{5 based, SiO 2 -B 2 O 3 -ZrO} 2 system or the like. In particular, SiO ₂ -B ₂ O ₃ -R ₂ O (R is an alkali metal) system is preferable because it is lead-free and has high adhesive strength after strain removal annealing.

The low melting inorganic component can also be added as a liquid, such as water glass. Water glass is particularly preferably sodium silicate. As an advantage of using water glass, since powder particles are not included, there are no irregularities due to particles on the coated surface, and a smooth surface can be easily obtained. In particular, when soda silicate is used, a high strength of 1.0 MPa or more can be obtained as the adhesive strength after strain removal annealing. When potassium silicate is used, a high strength of about 4.0 to 7.0 MPa can be obtained as the adhesive strength before deformation removal annealing.

As the low melting point inorganic component of the present invention, a mixture of colloidal silica may be used in addition to the inorganic component. By mixing colloidal silica or the like, the viscosity when the inorganic component is softened during strain removal annealing can be adjusted. In addition, even when the colloidal silica remains unsoftened during the strain removal annealing, the colloidal silica functions as an aggregate in the film, thereby increasing the adhesive strength after the strain removal annealing.

The resin applicable to the present invention can be applied to a thermosetting resin that causes a curing reaction when the steel sheets are bonded to each other by pressure and heating such as a phenol resin or an epoxy resin, as well as heating such as an acrylic resin or a methacryl resin. Even if it is a thermoplastic resin which hardening reaction does not occur, it is applicable. Although any of thermoplastic and thermosetting can be applied, it is preferable to have an adhesive action.

Although the resin of this invention softens at room temperature or more and 300 degrees C or less, in consideration of blocking property etc., fluidity | liquidity is expressed by the heating of 50 degreeC or more, 80 degreeC or more, 100 degreeC or more, especially 120 degreeC or more and 300 degrees C or less. It is preferable to soften to a degree. The softening of the degree to which fluidity | liquidity is expressed is based on what becomes a viscosity 1x10 <^8> dPa * s or less. As a mechanism in which the resin hardened | cured by heat-hardening on the steel plate surface is softened by the heating of 300 degrees C or less, the case where the hardened resin is a thermoplastic resin and the temperature which thermoplastics express is 120 degreeC or more and 300 degrees C or less is mentioned.

Moreover, as a mechanism of softening when resin is thermosetting, the case where it softens in a rubber state or a fluid state by heating to high temperature rather than glass transition temperature is mentioned. Particularly, in the case of a resin cured by a heat curing treatment for a short time of several tens of seconds or less at a low temperature of 200 ° C. or less, the crosslinking reaction to form a three-dimensional skeleton by heating proceeds, and once softened by going through a glass transition, When heated to a crosslinking reaction may proceed again to cure.

The acrylic modified epoxy resin emulsion which mix | blended the latent hardening | curing agent previously used as resin of this invention is after mix | blending a latent hardening | curing agent with an epoxy resin, chemically reacts an acrylic resin, and coats the circumference | surroundings of the mixture of an epoxy resin and a latent hardening | curing agent. It was made into an emulsion. The epoxy resin referred to here refers to a resin having two or more epoxy groups in the monomer, and includes bisphenol A type, bisphenol F type, bisphenol AD type, naphthalene type, phenol novolac type, orthocresol novolak type, glycidyl ester type, Alicyclic type; Examples of the latent curing agent include dicyandiamide, melamine, organic acid dihydrazide, amineimide, kelamine, tertiary amine salt, imidazole salt, boron trifluoride amine salt, microcapsule type curing agent, and molecular sieve type curing agent. . An acrylic resin is modified to the mixed system of the said epoxy resin and an epoxy resin hardener.

Modification here means bonding an acrylic resin chemically to the surface of an epoxy resin and an epoxy resin hardener mixture. The acrylic resin provided for such modification is polymerized or copolymerized one or two or more of methacrylic acid, methacrylic acid ester, acrylic acid, acrylic acid ester, styrene, vinyl acetate and the like. Although the compounding ratio of an epoxy resin and latent epoxy resin hardening | curing agent changes widely with the kind of epoxy resin and the kind of hardening | curing agent, 0.05-2 mass parts is suitable normally with respect to 1 mass part of epoxy resins. It is essential that the mixed liquid containing an acrylic modified epoxy resin emulsion in which a latent curing agent is blended in advance is applied to the surface of a steel sheet and then heat-cured in an incomplete state. The incomplete state does not cause sticking or blocking and shear processing. After lamination, it refers to a state of being bonded by pressure heating. Usually, it can heat-harden in an incomplete state by drying for 10 to 90 second at the furnace temperature of 100-300 degreeC.

Moreover, a siloxane polymer can be used as resin softened by heating. The siloxane polymer is a polymer in which the main skeleton is composed of an inorganic bond of Si-0-Si. Si is similar to C, and since Si can directly chemically bond with an organic group or H, such as Si-CH ₃ , Si-C ₆ H ₅ , and Si-H, a siloxane polymer having a skeleton composed of an organic group or H can be obtained.

One of four bonds of Si forms Si-R (R is an organic group or H) bond, and the other three form Si-O bonds. The number of bonds with Si through O in the T nucleus, that is, Rsi (-O-Si) ₃ , is called the T ₃ nucleus. Si core types can be analyzed by NMR. In general, Si nuclei forming the siloxane polymer include D nucleus and Q nucleus in addition to T nucleus. In the D nucleus, two of four bonds of Si form Si-R (R is an organic group or H) bond, and the other two form Si-0 bonds. In the Q nucleus, four of four bonds of Si form a Si-0 bond.

When Si in the T 3 nucleus repeats the bond according to a certain rule, a ladder molecule as shown in FIG. 2 is formed.

The aggregate composed of the ladder molecules can obtain a cured surface state in which entanglement of the ladder molecule chains is caused by application or heat curing, and no stickiness or blocking occurs. Molecular chains entangled above 100 ° C are released and exhibit fluidity. If it is in the range which shows fluidity | liquidity, Si core which an epoxy group couple | bonded may be included in addition to Si core which a methyl group couple | bonded.

The siloxane polymer of the present invention is obtained by hydrolysis under hydrochloric acid catalyst using one or both of organotrialkoxysilane or organotrichlorosilane as starting material. Examples of the organotrialkoxysilane include triethoxysilane, trimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane and propyltriethoxy Silane, isobutyltrimethoxysilane, isobutyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, glycidoxypropyltri Methoxysilane, glycidoxypropyltriethoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane and the like. Examples of the organotrichlorosilane include methyltrichlorosilane, ethyltrichlorosilane, phenyltrichlorosilane, and the like.

One or both of organotrialkoxysilane or organotrichlorosilane may be hydrolyzed after dispersion in an organic solvent. As the solvent, various alcohols such as methanol, ethanol, propanol and butanol, acetone, toluene, xylene and the like can be used. It is preferable that the mass ratio of the organic solvent with respect to the organoalkoxysilane at the time of hydrolysis is 1: 0.5-1: 2.

Hydrolysis is performed by adding 0.1 to 1 times the amount of water to the number of moles of all alkoxy groups in the starting material. Hydrochloric acid is added as a catalyst for hydrolysis. When organotrichlorosilane is used as a raw material, hydrochloric acid is formed as a by-product by adding water, so that hydrolysis is performed under a hydrochloric acid catalyst without any further action. Therefore, hydrochloric acid may not be added.

The hydrolyzed sol is usually made into a siloxane polymer by promoting the polycondensation reaction by a process such as concentration. Concentration is preferably carried out using a rotary evaporator to remove the organic solvent, the by-product alcohol and the like so that the mass of the concentrate is about 15 to 60% of the mass of the solution before concentration. As a method other than concentration, an alkali such as potassium hydroxide (KOH) may be added and refluxed in a nitrogen atmosphere to accelerate the polycondensation reaction to obtain a siloxane polymer. The obtained siloxane polymer is diluted to about 1.5 to 10 times with an organic solvent or water to obtain a coating liquid. Usually, it heats and hardens for 15 to 120 second at 100-200 degreeC, and it will be in the state adhere | attached by pressure heating.

In addition, depending on the conditions of heating and annealing, the resin and the low-melting-point inorganic component in the present invention may not be apparently melted in the coating film of the present invention and the grains may appear to remain as they are. When the adhesion function is expressed by annealing, there is no problem in the present invention.

The present invention can be applied to any type of oriented electrical steel sheet, non-oriented electrical steel sheet, etc., as long as it is an electronic steel sheet manufactured by ordinary rolling and annealing, but especially when applied to a non-oriented electrical steel sheet for motor iron core. You can exercise a lot.

In the conventional manufacturing method of a grain-oriented electrical steel sheet or a non-oriented electrical steel sheet, both steel sheets form a surface film on the surface of a steel plate by finishing annealing. In the case of a grain-oriented electrical steel sheet, a phosphate-based film containing a silica component is formed, and in the case of a non-oriented electrical steel sheet, a chromate-based film is formed. In particular, in the case of a grain-oriented electrical steel sheet, a method of forming a forsterite silicate film during the finish annealing, a method of intentionally not forming, a method of removing the resultant forsterite film by means of pickling, etc. There is this. The present invention can be applied with or without such various surface coatings.

The electrical steel sheet with a heat-resistant adhesive insulating film of this invention apply | coats the coating liquid containing a heat-resistant adhesive insulating film composition to an electronic steel plate by methods, such as a roll coater, a bar coater, a flow coater, a dip coater, and a spray. The coating amount is preferably 1 g / m ² or more and 30 g / m ² or less, particularly 2 g / m ² or more and 10 g / m ² or less.

The heat-resistant adhesive insulating film composition is preferably a mixture of a resin and a low-melting-point inorganic component, but both may be dispersed and mixed in a lump form, or both may be coated separately. The low melting inorganic component may be dispersed in the shape of dots, stripes, etc. in the matrix by the organic component, and the organic component may be dispersed in the shape of dots, stripes, etc. in the inorganic matrix by siloxane bonds or the like.

The film thickness is preferably 0.5 µm or more and 20 µm or less per surface. If the film thickness is less than 0.5 µm, it is difficult to sufficiently cover the entire surface on the steel sheet, so that sufficient adhesive strength is not obtained. If the film thickness is larger than 20 µm, the droplet ratio greatly decreases when pressurized and heated. Therefore, the film thickness is preferably 0.5 µm or more and 20 µm or less.

The coating composition of this invention is apply | coated to the surface of an electrical steel sheet, and is heat-hardened first so that stickiness or blocking may not generate | occur | produce. After apply | coating, the electrical steel plate with a heat-resistant adhesive insulating film can be produced by heat-hardening at 50-200 degreeC. Although this process may be performed just before iron core punching or iron core lamination, it is especially preferable to apply | coat it at the time of steel plate manufacture, and to make it the electrical steel plate of a so-called pre-coat state in order to simplify an iron core manufacturing process. The resin is softened by heating to a temperature higher than the heat curing temperature when laminating and blocking the steel sheet fragments punched out in the desired shape from this steel sheet.

In the case where hot pressing is performed by laminating an electronic steel sheet having both surfaces of the film of the present invention, the softened resin is integrally formed by heating at the time of hot pressing, so that the electronic steel sheet can be bonded during cooling.

In addition, when the electronic steel sheet fragments having only one side of the coating film of the present invention are laminated in the same direction, the softened resin component is uniformly spread by heating on the surface of the electronic steel sheet fragment without the coating layer of the present invention, so that it is adhered at the time of cooling. can do. Since high temperature hot press has high cost, it is preferable that hot press temperature is 300 degrees C or less. It is preferable that they are 0.1 MPa or more and 50 MPa or less, and it is especially preferable that they are 1 MPa or more and 20 MPa or less. When the pressure of the hot press is low, since sufficient adhesiveness cannot be obtained, it is difficult to integrate the iron core. If the pressure of the hot press is high, the adhesive layer may flow and come out between the layers.

The electrical steel sheet of the present invention can be integrated into an iron core when punched into a desired shape, laminated, pressurized and heated. Thereafter, even when the strain removal annealing is performed as necessary, the adhesive performance between the laminated steel sheets is maintained. The temperature of strain removal annealing is normally 650 degreeC or more and 850 degrees C or less, and is often performed at 700 degreeC or more and 800 degrees C or less.

Moreover, since the film of this invention has adhesive performance even without performing annealing, such as strain removal annealing, it can use also for the iron core which does not perform deformation removal annealing. That is, it can use as an adhesive film for the combined use for distortion removal annealing and the non-deformation removal annealing.

In addition, in the case of strain removal annealing, when fixing by pressurization and heating, fixation by caulking or a jig can also be used together.

1 shows a typical differential thermal analysis curve of glass.

2 shows a ladder-shaped siloxane polymer.

Hereinafter, an embodiment will be described.

Example 1

Acrylic resin: Epoxy resin: Phenolic resin = 10: 4: 3 (mass%) The solution which mixes the glass frit which has various particle diameters at 450 degreeC with the resin aqueous dispersion of 20 mass% of solid content ratio is prepared. It was. Resin / glass frit mixing ratio in the liquid which mix | blended glass frit was made to be 200%. The coating liquid was applied to a finish-annealed non-oriented electrical steel sheet having a plate thickness of 0.5 mm and not having an insulating coating on the surface of the steel sheet so that the coating amount was 6 g / m ² per surface with a roll coater. Next, it dried and cooled at the drying temperature of 150 degreeC. The film thickness per side was 10 micrometers. In this way, the test piece which cut out the dimension of 10 cm of rolling direction length and 3 cm of perpendicular | vertical direction with respect to a rolling direction was cut out from the produced sample. Then, ^two test pieces were overlapped with a length of 1 cm and a overlapping area of 3 cm ² at a short side, and heated to 250 ° C. in a state pressurized at 10 kg / cm ² , held for 60 seconds, and cooled to prepare a test piece for measuring 250 ° C. adhesive strength. Moreover, about a part of test piece for 250 degreeC adhesive strength measurements, the test piece for 750 degreeC adhesive strength measurements was prepared by heating to 750 degreeC, holding for 2 hours, and cooling it, under a load. Adhesive strength was measured about the test piece prepared in this way using the tensile tester. The results are shown in Table 4.

In Table 4, in the sample group in which the average particle diameter of the glass frit of the condition numbers 1 to 5 was 2 micrometers-20 micrometers, 250 degreeC adhesive strength is 10 kg / cm <^2> or more, and 750 degreeC adhesive strength is also 1kg / cm <^2> or more. On the other hand, in the sample whose average particle diameter of the glass frit of Condition No. 6 was 25 micrometers, 250 degreeC adhesive strength was 5 kg / cm <^2> and 750 degreeC adhesive strength was not so small that it was not favorable.

The Example whose average particle diameter of a glass frit is 20 micrometers or less is excellent compared with the comparative example whose average particle diameter is 25 micrometers.

Example 2

Acrylic resin: epoxy resin: phenolic resin = 11: 3: 4 to the number of resins in a solid component ratio of 20 mass% of the composition dispersion of (% by mass), the composition of B ₂ O ₃ = 25% by weight, SiO ₂ = 65% by mass, Na ₂ O = 10% by mass and a liquid containing a glass frit (Example) having a linear thermal expansion coefficient of 40 × 10 ⁻⁷ (° C. ⁻¹ ) at 30 ° C. to 300 ° C., and the resin aqueous dispersion. Glass whose coefficient of linear thermal expansion at 300 ° C. is 300 × 10 ⁻⁷ (° C. ⁻¹ ) at 30 ° C. having a composition of B ₂ O ₃ = 50 mass%, SiO ₂ = 25 mass%, K ₂ 0 = 25 mass%. The liquid which mixed the frit (comparative example) was prepared. The glass frit used what has an average particle diameter of 10 micrometers. In addition, all the resin / glass frit mixing ratios in the liquid which mix | blended the glass frit were made to be 100%.

This coating liquid was applied to a finish-annealed non-oriented electrical steel sheet having a plate thickness of 0.5 mm and having a magnesium chromium-based insulating film on the surface of the steel sheet so that the coating amount was 8 g / m ² per surface with a roll coater. Next, it dried and cooled at the drying temperature of 140 degreeC. The film thickness per side was 6 micrometers. In this way, an annular sample having an inner diameter of 10.16 cm (4 inches) and an outer diameter of 12.7 cm (5 inches) was produced, and 20 sheets were laminated, and the film was heated at a pressure of 10 kg / cm ² and a temperature of 250 ° C. for 4 hours. An adhesive iron core was produced. Next, the iron core was annealed at a temperature of 750 ° C. for 2 hours without pressing the iron core. Finally, the iron loss was measured using a frequency of 50 Hz and a magnetic flux density of 1.5 tesla. The results are shown in Table 5.

In Table 5, the iron loss of the iron core produced using the glass frit having the linear thermal expansion coefficient of Condition No. 1 of 40 × 10 ⁻⁷ (° C. ⁻¹ ) was good at 3.05 (W / kg). The iron loss of the iron core produced using the glass frit having a linear thermal expansion coefficient of 170 × 10 ⁻⁷ (° C. ⁻¹ ) was 3.27 (W / kg), which was not good. Thus, it turns out that the Example by this invention is excellent compared with a comparative example.

Example 3

The following four types were produced as a coating liquid.

Coating liquid A

40 mass parts of acrylic modified epoxy resin emulsion which mix | blended 20 mass% of latent hardeners with respect to 100 mass parts of water, and 5 mass parts of methyl ethyl ketone were mix | blended. The glass transition temperature of resin obtained by apply | coating and heat-hardening this coating liquid was 104 degreeC, and was softened at 120 degreeC or more.

Coating liquid B

100 mass parts of water, 40 mass parts of acrylic resin emulsion, 40 mass parts of epoxy resin emulsion, and 4 mass parts of amine epoxy hardening | curing agent were mix | blended. The resin obtained by apply | coating and heat-hardening this coating liquid softened at 150 degreeC or more.

Coating liquid C

Into a mixed solution of 178 g of methyltriethoxysilane and 138 g of ethanol, an aqueous solution of 35.3 g of water and 1.04 g of 35% hydrochloric acid was added dropwise, followed by hydrolysis. The hydrolyzed solution was concentrated using a rotary evaporator at 58 ° C. until no solvent emerged. The mass of the concentrate was 30% of the mass of the solution before concentration. The mass average molecular weight of this concentrate was 10000. Since this concentrate showed a sharpness, it can be considered that methyltriethoxysilane is polymerized in the form of a chain polymer. The concentrate was heat-treated at 70 ° C. for 15 minutes, which resulted in solidification but softened near 180 ° C. 200 mass parts of ethanol was mix | blended with respect to 100 mass parts of this concentrates.

Coating liquid D

178 g of methyltriethoxysilane and 152 g of tetramethoxysilane are dispersed in 270.3 g of 2-ethoxyethanol. A coating liquid was prepared by hydrolysis by adding 4.8 g of acetic acid as a catalyst and adding 36 g of water. This siloxane polymer was not softened by heating.

In Table 6, the temperature described in parentheses after the glass composition of the interruption of the coating liquid is the softening temperature of the glass. All of the glasses shown in Table 6 are powders having an average particle diameter of 2 µm. The Example and the comparative example apply | coated each coating liquid to the both sides of the 0.5 mm-thick non-oriented electrical steel sheet by the roll coater, and heat-hardened for 15 minutes in the furnace set to 70 degreeC. The coating amount was 7 g / m ² . There was no stickiness of the film surface after heat curing in all.

Two test pieces having a width of 3 cm and a length of 10 cm were used, and a part of the test pieces was overlapped so as to have an area of the adhesive portion of 6 cm ² and hot pressed. Before the hot press, the applied film other than the adhesive portion was scraped off. Two test pieces were bonded by hot press of 200 degreeC, 1 minute, and 10 MPa. Strain removal annealing was performed at 750 ° C. for 2 hours in nitrogen. The adhesive strength before and after strain removal annealing was evaluated using the shear tensile strength which is the horizontal strength of the bonded surface.

In Comparative Example 1, since the softening temperature was higher than that of the strain removal annealing temperature, there was no adhesiveness after annealing. In Comparative Example 2, since the resin was not softened by heating, it could not be bonded by hot pressing. Since the comparative example 3 did not contain the low melting glass, adhesiveness could not be obtained after strain removal annealing.

Example 4

The following four types were produced as a coating liquid.

Coating liquid A

40 mass parts of acrylic modified epoxy resin emulsion which mix | blended 20 mass% of latent hardeners with respect to 100 mass parts of water, and 5 mass parts of methyl ethyl ketone were mix | blended. The glass transition temperature of resin obtained by apply | coating and heat-hardening this coating liquid was 104 degreeC, and was softened at 120 degreeC or more.

Coating liquid B

100 mass parts of water, 40 mass parts of acrylic resin emulsion, 40 mass parts of epoxy resin emulsion, and 4 mass parts of amine epoxy hardening | curing agent were mix | blended. The resin obtained by apply | coating and heat-hardening this coating liquid softened at 150 degreeC or more.

Coating liquid C

Into a mixed solution of 178 g of methyltriethoxysilane and 138 g of ethanol, an aqueous solution of 35.3 g of water and 1.04 g of 35% hydrochloric acid was added dropwise to perform hydrolysis. The hydrolyzed solution was concentrated using a rotary evaporator at 58 ° C. until no solvent emerged. The mass of the concentrate was 30% of the mass of the solution before concentration. The mass average molecular weight of this concentrate was 10000. Since this concentrate showed a sharpness, it can be considered that methyltriethoxysilane is polymerized in the form of a chain polymer. The concentrate was heat-treated at 70 ° C. for 15 minutes, which resulted in solidification but softened near 180 ° C. 200 mass parts of ethanol was mix | blended with respect to 100 mass parts of this concentrates.

In Examples, the coating liquids A to C were diluted with water, and then various water glasses were added to prepare a coating liquid. The Example and the comparative example apply | coated each coating liquid to the both sides of the 0.5 mm-thick non-oriented electrical steel sheet by the roll coater, and heat-hardened for 15 minutes in the furnace set to 70 degreeC. The coating amount was 10 g / m ² . There was no stickiness of the film surface after heat curing in all.

Two test pieces having a width of 3 cm and a length of 10 cm were used, and a part of the test pieces was overlapped so as to have an area of the adhesive portion of 6 cm ² and hot pressed. Before the hot press, the applied film other than the adhesive portion was scraped off. Two test pieces were bonded by 200 degreeC, 1 minute, 10 MPa hot press. Strain removal annealing was performed at 750 ° C. for 2 hours in nitrogen. The adhesive strength before and after strain removal annealing was evaluated using the shear tensile strength which is the horizontal strength of the bonded surface.

Example 5

Coating liquid D described in Example 3 was prepared. 10 mass parts of spherical particles of polyester whose average particle diameter is 4 micrometers, and a softening temperature are 200 degreeC with respect to coating liquid D00 mass part were mixed and dispersed. After apply | coating with the roll coater to the non-oriented electrical steel plate with which the surface film by inorganic-organic mixed process liquid was formed, it heat-hardened for 2 minutes in the furnace set to 100 degreeC. The coating amount was 10 g / m ² . Two test pieces having a width of 3 cm and a length of 10 cm were used, and a part of the test pieces was overlapped so as to have an area of the adhesive portion of 6 cm ² and hot pressed. Before the hot press, the applied film other than the adhesive portion was scraped off. Two test pieces were bonded by hot press of 230 degreeC, 1 minute, and 10 Mpa. Strain removal annealing was performed at 750 ° C. for 2 hours in nitrogen. The adhesive strength before and after strain removal annealing was evaluated using the shear tensile strength which is the horizontal strength of the bonded surface. The adhesive strengths before and after strain removal annealing were 1.0 MPa and 2.1 MPa, respectively.

According to the present invention, after punching or shearing, an electric steel sheet with a heat-resistant adhesive insulating film which can be bonded by pressure and heating and integrated with an iron core, and which can maintain adhesive performance even after further performing strain removal annealing Can provide. Iron cores can be integrated without welding and caulking, and deterioration of iron loss due to welding and caulking can be avoided, and even after deformation removal annealing, the adhesive state and insulation can be maintained, thereby making it possible to produce iron cores having excellent magnetic properties.

Claims (14)

The heat-resistant adhesive insulating film containing resin whose softening point temperature is more than room temperature and 300 degrees C or less, and the low melting-point inorganic component whose softening point temperature is 1000 degrees C or less. The method of claim 1, A heat resistant adhesive insulating film, characterized in that the 250 ℃ adhesive strength = 10kg / cm ² or more, 750 ℃ adhesive strength = 1kg / cm ² or more. The method of claim 1, The linear thermal expansion coefficient in 30 degreeC-300 degreeC is 10 * ^10-7 (degreeC- ¹ ) or more and 150 * ^10-7 (degreeC- ¹ ) or less, The heat-resistant adhesive insulating film characterized by the above-mentioned. The method of claim 1, The low-melting-point inorganic component is a low-melting-point glass frit, water glass, or a heat-resistant adhesive insulating film in which colloidal silica is further mixed with these. The method of claim 4, wherein A heat-resistant adhesive insulating film, wherein the average particle diameter of the low melting inorganic component is 20 µm or less. The method of claim 4, wherein A heat-resistant adhesive insulating film, wherein the mixing ratio of the resin to the low-melting-point inorganic component is 20% or more and 500% or less by mass fraction. The method of claim 4, wherein A low-melting-point inorganic component is a SiO ₂ -B ₂ O ₃ -R ₂ O-based low melting glass (R is an alkali metal), a heat-resistant adhesive insulating film. The method of claim 4, wherein A heat-resistant adhesive insulating film, wherein the water glass is soda silicate. The method of claim 1, The resin contains one or two or more selected from epoxy resins, acrylic resins, phenolic resins, resins or siloxane polymers in which a mixed solution containing an acrylic modified epoxy resin emulsion containing a latent curing agent as a main component is heat-cured in an incomplete state. Heat-resistant adhesive insulating film, characterized in that. An electronic steel sheet with a heat-resistant adhesive insulating film, having the film according to claim 1 on at least one surface of the steel sheet. The electrical steel sheet with a heat resistant adhesive insulating film according to claim 10, wherein the heat resistant adhesive insulating film has a film thickness of 0.5 µm or more and 20 µm or less. Iron core using the electrical steel plate with a heat-resistant adhesive insulating film of Claim 10. The manufacturing method of the iron core using the electronic steel plate with a heat-resistant adhesive insulating film which laminates and pressure-fixes the electronic steel plate of Claim 10, produces an electronic steel plate laminated body, and then performs annealing at 600-900 degreeC, and obtains an integrated iron core. The method of claim 13, A method for producing an iron core using an electrical steel sheet with a heat-resistant adhesive insulating coating, characterized in that at least in the pressure-fixing step, heating is carried out to fix and fix, or to fix by caulking or jig.

Images